Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Goes well beyond the readOnly/idempotent/non-destructive annotations by disclosing link lifetime (6 hours), the dependency on a prior export, the failure mode when the export is not ready, and the paid-account requirement. These are exactly the constraints an agent would otherwise discover only by failing.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Three tight sentences, front-loaded with the return value and lifetime, followed by failure/eligibility conditions and the response shape. No sentence is filler.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With no output schema, the description carries the return contract itself ('url' as .tar.gz and 'expiresAt'), plus latency-relevant failure conditions and account eligibility. Nothing material an agent needs before calling it is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The description says nothing about the single nested path object (backupId, serverId); it relies entirely on the schema, whose nested properties do carry their own descriptions pointing to listBackups and listServers. Coverage is nominally low at the top level, so this is adequate but not compensating.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('Returns a signed link ... to download a backup') and explicitly scopes it to backups produced by the sibling tool startBackupExport, which distinguishes it from listBackups, deleteBackupExport, and restoreBackup. An agent can route to it without opening the schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Clear preconditions are given: must be used after startBackupExport, fails if the export is not ready, and requires a paid account. It does not, however, point at an alternative (e.g., how to check readiness or what to call for a non-exported backup).

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.